Forest disturbance and vector transmitted diseases in the lowland tropical rainforest of central Panama.

OBJECTIVE: To explore possible changes in the community attributes of haematophagous insects as a function of forest disturbance. We compare the patterns of diversity and abundance, plus the behavioural responses of three epidemiologically distinct vector assemblages across sites depicting various levels of forest cover. METHODS: Over a 3-year period, we sampled mosquitoes, sandflies and biting-midges in forested habitats of central Panama. We placed CDC light traps in the forest canopy and in the understorey to gather blood-seeking females. RESULTS: We collected 168 405 adult haematophagous dipterans in total, including 26 genera and 86 species. Pristine forest settings were always more taxonomically diverse than the disturbed forest sites, confirming that disturbance has a negative impact on species richness. Species of Phlebotominae and Culicoides were mainly classified as climax (i.e. forest specialist) or disturbance-generalist, which tend to decrease in abundance along with rising levels of disturbance. In contrast, a significant portion of mosquito species, including primary and secondary disease vectors, was classified as colonists (i.e. disturbed-areas specialists), which tend to increase in numbers towards more disturbed forest habitats. At pristine forest, the most prevalent species of Phlebotominae and Culicoides partitioned the vertical niche by being active at the forest canopy or in the understorey; yet this pattern was less clear in disturbed habitats. Most mosquito species were not vertically stratified in their habitat preference. CONCLUSION: We posit that entomological risk and related pathogen exposure to humans is higher in pristine forest scenarios for Culicoides and Phlebotominae transmitted diseases, whereas forest disturbance poses a higher entomological risk for mosquito-borne infections. This suggests that the Dilution Effect Hypothesis (DEH) does not apply in tropical rainforests where highly abundant, yet unrecognised insect vectors and neglected zoonotic diseases occur. Comprehensive, community level entomological surveillance is, therefore, the key for predicting potential disease spill over in scenarios of pristine forest intermixed with anthropogenic habitats. We suggest that changes in forest quality should also be considered when assessing arthropod-borne disease transmission risk.

OBJECTIF: Explorer les changements possibles dans les attributs communautaires des insectes hématophages en fonction de la perturbation des forêts. Nous comparons les modèles de diversité et d'abondance, ainsi que les réponses comportementales de trois assemblages de vecteurs épidémiologiquement distincts sur des sites illustrant divers niveaux de couverture forestière. MÉTHODES: Au cours d'une période de trois ans, nous avons échantillonné des moustiques, des phlébotomes et des moucherons piqueurs dans les habitats forestiers du centre de Panama. Nous avons placé des pièges à lumière CDC dans la canopée de la forêt et dans le sous-étage pour recueillir les femelles en quête de sang. RÉSULTATS: Nous avons collecté un total de 168.405 diptères hématophages adultes, dont 26 genres et 86 espèces. Les environnements de forêt intacts étaient toujours plus diversifiés du point de vue taxonomique que les sites forestiers perturbés, confirmant que les perturbations avaient un impact négatif sur la richesse en espèces. Les espèces de phlébotome et Culicoïdes étaient principalement classés comme climax (spécialiste de la forêt) ou généralistes de perturbation, qui ont tendance à diminuer en abondance parallèlement aux niveaux croissants de perturbation. En revanche, une partie importante des espèces de moustiques, y compris les vecteurs primaires et secondaires de maladies, a été classée dans la catégorie des colons (c'est-à-dire spécialistes des zones perturbées), qui ont tendance à se multiplier vers des habitats forestiers plus perturbés. Dans la forêt vierge, les espèces de phlébotomes et Culicoïdes les plus répandues cloisonnaient la niche verticale en étant actives dans la canopée de la forêt ou dans le sous-étage; pourtant, cette tendance était moins nette dans les habitats perturbés. La plupart des espèces de moustiques n'étaient pas stratifiées verticalement dans leur préférence d'habitat. CONCLUSION: Nous estimons que le risque entomologique et l'exposition associée des agents pathogènes à l'homme est plus élevé dans les scénarios de forêt vierge pour les maladies transmises par les phlébotomes et Culicoïdes, alors que la perturbation des forêts pose un risque entomologique plus élevé pour les infections transmises par les moustiques. Cela suggère que l'hypothèse de l'effet de dilution ne s'applique pas dans les forêts tropicales humides où se reproduisent très abondamment les insectes vecteurs, mais non reconnus, et où des maladies zoonotiques négligées surviennent. Une surveillance entomologique approfondie au niveau de la communauté est donc la clé pour prédire le potentiel de propagation des maladies dans des scénarios de forêt vierge mélangée à des habitats anthropiques. Nous suggérons que les changements dans la qualité des forêts soient également pris en compte lors de l'évaluation du risque de propagation de maladies transmises par les arthropodes.

A new graphene-based nanomaterial increases lipolysis and reduces body weight gain through integrin linked kinase (ILK).

White adipose tissue (WAT) hypertrophy is caused by the excessive storage of triglycerides (TGs) and is associated with obesity. We previously demonstrated that extracellular matrix mediator integrin beta1 (INTB1) and its downstream effector integrin linked kinase (ILK) are implicated in obesity establishment. We also considered in our previous works that ILK upregulation is a therapeutical strategy to reduce WAT hypertrophy. Carbon based nanomaterials (CNMs) have interesting potential to modify cell differentiation but have been never studied to change the properties of adipocytes. METHODS: GMC is a new graphene-based CNM that was tested for biocompatibility and functionality in cultured adipocytes. MTT, TG content, lipolysis quantification, and transcriptional changes were determined. Specific INTB1 blocking antibody and ILK depletion with specific siRNA were used to study the intracellular signalling. We complemented the study using subcutaneous WAT (scWAT) explants from transgenic ILK knockdown mice (cKD-ILK). GMC was topically administrated in the dorsal area of high fat diet-induced obese rats (HFD) for 5 consecutive days. The scWAT weights and some intracellular markers were analyzed after the treatment. RESULTS: graphene presence was characterized in GMC. It was non-toxic and effective in reducing TG content in vitro in a dose-dependent manner. GMC rapidly phosphorylated INTB1 and increased the expression and activity of hormone sensitive lipase (HSL), the lipolysis subproduct glycerol, and the expression of glycerol and fatty acid transporters. GMC also reduced the expression of adipogenesis markers. Pro-inflammatory cytokines were unaffected. ILK was overexpressed, and INTB1 or ILK blockade avoided functional GMC effects. Topical administration of GMC in HFD rats overexpressed ILK in scWAT, and their weight gains were reduced, while systemic (renal, hepatic) toxicity parameters were unaffected. CONCLUSIONS: GMC is safe and effective in reducing hypertrophied scWAT weight when topically applied and it can be considered of interest in anti-obesogenic strategies. GMC increases lipolysis and reduces adipogenesis inside adipocytes by mechanisms that imply the activation of INTB1, the overexpression of ILK, and changes in the expression and activity of several markers related to fat metabolism.

The role of heterogenous environmental conditions in shaping the spatiotemporal distribution of competing Aedes mosquitoes in Panama: implications for the landscape of arboviral disease transmission.

Monitoring the invasion process of the Asian tiger mosquito Aedes albopictus and its interaction with the contender Aedes aegypti, is critical to prevent and control the arthropod-borne viruses (i.e., Arboviruses) they transmit to humans. Generally, the superior ecological competitor Ae. albopictus displaces Ae. aegypti from most geographic areas, with the combining factors of biology and environment influencing the competitive outcome. Nonetheless, detailed studies asserting displacement come largely from sub-tropical areas, with relatively less effort being made in tropical environments, including no comprehensive research about Aedes biological interactions in Mesoamerica. Here, we examine contemporary and historical mosquito surveillance data to assess the role of shifting abiotic conditions in shaping the spatiotemporal distribution of competing Aedes species in the Republic of Panama. In accordance with prior studies, we show that Ae. albopictus has displaced Ae. aegypti under suboptimal wet tropical climate conditions and more vegetated environments within the southwestern Azuero Peninsula. Conversely, in the eastern Azuero Peninsula, Ae. aegypti persists with Ae. albopictus under optimal niche conditions in a dry and more seasonal tropical climate. While species displacement was stable over the course of two years, the presence of both species generally appears to fluctuate in tandem in areas of coexistence. Aedes albopictus was always more frequently found and abundant regardless of location and climatic season. The heterogenous environmental conditions of Panama shape the competitive outcome and micro-geographic distribution of Aedes mosquitoes, with potential consequences for the transmission dynamics of urban and sylvatic zoonotic diseases. SUPPLEMENTARY INFORMATION: The online version of this article (10.1007/s10530-021-02482-y).

Late Pleistocene environmental changes lead to unstable demography and population divergence of Anopheles albimanus in the northern Neotropics.

We investigated the historical demography of Anopheles albimanus using mosquitoes from five countries and three different DNA regions, the mitochondrial cytochrome oxidase subunit I gene (COI), the single copy nuclear white gene and the ribosomal internal transcribed spacer two (ITS2). All the molecular markers supported the taxonomic status of a single species of An. albimanus. Furthermore, agreement between the COI and the white genes suggested a scenario of Pleistocene geographic fragmentation (i.e., population contraction) and subsequent range expansion across southern Central America.

Aedes Mosquito Infestation in Socioeconomically Contrasting Neighborhoods of Panama City.

The global expansion and proliferation of Aedes aegypti and Aedes albopictus represents a growing public health threat due to their capacity to transmit a variety of arboviruses to humans, including dengue, chikungunya, and Zika. Particularly important in urban regions, where these species have evolved to breed in man-made containers and feed nearly exclusively on human hosts, the threat of vector-borne disease has risen in recent decades due to the growth of cities, progression of climate change, and increase in globalization. While the dynamics of Aedes populations in urban settings have been well studied in relation to ecological features of the landscape, relatively less is known about the relationship between neighborhood socioeconomic status and Aedes infestation. Here, we compare infestation levels of both A. aegypti and A. albopictus in four socioeconomically contrasting neighborhoods of urban Panama City, Panama. Our results indicate that infestation levels for both Aedes species vary between neighborhoods of contrasting socioeconomic status, being higher in neighborhoods having lower percentage of residents with bachelor degrees and lower monthly household income. Additionally, we find that proximity between socioeconomically contrasting neighborhoods can predict infestation levels by species, with A. aegypti increasing and A. albopictus decreasing with proximity between neighborhoods. These findings hold key implications for the control and prevention of dengue, chikungunya, and Zika in Panama, a region with ongoing arbovirus outbreaks and high economic inequity.

Dynamics and diversity of bacteria associated with the disease vectors Aedes aegypti and Aedes albopictus.

Aedes aegypti and Aedes albopictus develop in the same aquatic sites where they encounter microorganisms that influence their life history and capacity to transmit human arboviruses. Some bacteria such as Wolbachia are currently being considered for the control of Dengue, Chikungunya and Zika. Yet little is known about the dynamics and diversity of Aedes-associated bacteria, including larval habitat features that shape their tempo-spatial distribution. We applied large-scale 16S rRNA amplicon sequencing to 960 adults and larvae of both Ae. aegypti and Ae. albopictus mosquitoes from 59 sampling sites widely distributed across nine provinces of Panama. We find both species share a limited, yet highly variable core microbiota, reflecting high stochasticity within their oviposition habitats. Despite sharing a large proportion of microbiota, Ae. aegypti harbours higher bacterial diversity than Ae. albopictus, primarily due to rarer bacterial groups at the larval stage. We find significant differences between the bacterial communities of larvae and adult mosquitoes, and among samples from metal and ceramic containers. However, we find little support for geography, water temperature and pH as predictors of bacterial associates. We report a low incidence of natural Wolbachia infection for both Aedes and its geographical distribution. This baseline information provides a foundation for studies on the functions and interactions of Aedes-associated bacteria with consequences for bio-control within Panama.

High infestation of invasive Aedes mosquitoes in used tires along the local transport network of Panama.

BACKGROUND: The long-distance dispersal of the invasive disease vectors Aedes aegypti and Aedes albopictus has introduced arthropod-borne viruses into new geographical regions, causing a significant medical and economic burden. The used-tire industry is an effective means of Aedes dispersal, yet studies to determine Aedes occurrence and the factors influencing their distribution along local transport networks are lacking. To assess infestation along the primary transport network of Panama we documented all existing garages that trade used tires on the highway and surveyed a subset for Ae. aegypti and Ae. albopictus. We also assess the ability of a mass spectrometry approach to classify mosquito eggs by comparing our findings to those based on traditional larval surveillance. RESULTS: Both Aedes species had a high infestation rate in garages trading used tires along the highways, providing a conduit for rapid dispersal across Panama. However, generalized linear models revealed that the presence of Ae. aegypti is associated with an increase in road density by a log-odds of 0.44 (0.73 ± 0.16; P = 0.002), while the presence of Ae. albopictus is associated with a decrease in road density by a log-odds of 0.36 (0.09 ± 0.63; P = 0.008). Identification of mosquito eggs by mass spectrometry depicted similar occurrence patterns for both Aedes species as that obtained with traditional rearing methods. CONCLUSIONS: Garages trading used tires along highways should be targeted for the surveillance and control of Aedes-mosquitoes and the diseases they transmit. The identification of mosquito eggs using mass spectrometry allows for the rapid evaluation of Aedes presence, affording time and cost advantages over traditional vector surveillance; this is of importance for disease risk assessment.

Maternal invasion history of Aedes aegypti and Aedes albopictus into the Isthmus of Panama: Implications for the control of emergent viral disease agents.

Despite an increase in dengue outbreaks and the arrival of chikungunya and Zika disease in Panama, studies on the demographic history of the invasive Aedes mosquitoes that are the principle vectors of these diseases are still lacking in this region. Here, we assess the genetic diversity of these mosquitoes in order to decipher their invasion histories into the Isthmus of Panama. DNA sequences from the mitochondrial cytochrome C oxidase I gene obtained from 30 localities in 10 provinces confirmed the presence of more than one mitochondrial haplogroup (i.e., maternal lineage) in each species. The invasion of Aedes albopictus was likely from temperate European countries, as the most frequent and widespread haplogroup in Panama harbored variants that are uncommon elsewhere in the Americas. Two infrequent and geographically restricted Ae. albopictus haplotypes appear to have subsequently invaded Panama from neighboring Costa Rica and the USA, respectively. In addition, we recovered two deeply divergent mitochondrial clades in Panamanian Aedes aegypti. The geographic origins of these clades is unknown, given that divergence in the mitochondrial genome is probably due to ancient population processes within the native range of Ae. aegypti, rather than due to its global expansion out of Africa. However, Panamanian Ae. aegypti mitochondrial sequences within the first clade were closely related to others from Colombia, Bolivia, Brazil, Mexico and the USA, suggesting two separate invasions from Western Hemisphere source populations. The pattern of increased genetic diversity in Aedes mosquitoes in Panama is likely facilitated by the numerous land and water inter-connections across the country, which allows them to enter via sea- and land-transportation from Europe, North, Central and South America. Our results here should be considered in disease mitigation programs if emergent arboviruses are to be effectively diminished in Panama through vector suppression.

Disturbance and mosquito diversity in the lowland tropical rainforest of central Panama.

The Intermediate Disturbance Hypothesis (IDH) is well-known in ecology providing an explanation for the role of disturbance in the coexistence of climax and colonist species. Here, we used the IDH as a framework to describe the role of forest disturbance in shaping the mosquito community structure, and to identify the ecological processes that increase the emergence of vector-borne disease. Mosquitoes were collected in central Panama at immature stages along linear transects in colonising, mixed and climax forest habitats, representing different levels of disturbance. Species were identified taxonomically and classified into functional categories (i.e., colonist, climax, disturbance-generalist, and rare). Using the Huisman-Olff-Fresco multi-model selection approach, IDH testing was done. We did not detect a unimodal relationship between species diversity and forest disturbance expected under the IDH; instead diversity peaked in old-growth forests. Habitat complexity and constraints are two mechanisms proposed to explain this alternative postulate. Moreover, colonist mosquito species were more likely to be involved in or capable of pathogen transmission than climax species. Vector species occurrence decreased notably in undisturbed forest settings. Old-growth forest conservation in tropical rainforests is therefore a highly-recommended solution for preventing new outbreaks of arboviral and parasitic diseases in anthropic environments.

Assisted laparoscopic transhiatal esophagectomy for the treatment of esophageal cancer.

BACKGROUND: Esophageal resection for the treatment of esophageal cancer is usually associated with high morbido-mortality risks, that can be reduced using laparoscopy. Laparoscopic transhiatal esophagectomy (LTE) has the potential to improve these results but, to-date, only a few limited series of cases have been reported. This report summarizes our experience in 24 cases. OBJECTIVE: To assess the outcomes following LTE. METHODS AND MATERIALS: Between 1998 and 2005, LTE was performed in 24 patients; 18 men and 6 women with an overall mean age of 63 years (range: 36-85). Indication for surgery was lower third esophageal cancer; 11 squamous cell carcinoma and 13 adenocarcinoma. Neoadjuvant chemotherapy and radiotherapy were used in 18 patients (75%). A laparoscopic transhiatal approach was used to perform an esophagectomy with curative intent. A cervical esophagogastric anastomosis was created. RESULTS: No reversion to conventional open surgery was required. Mean anesthesia time was 293.8 min (range: 255-360). Major complications occurred in 7 patients (29.2%). Two patients (8.3%) had leakage from the cervical anastomosis. Surgical mortality was 8.3%. The median stay in Intensive Care Unit was 5 days (range: 1-29). Median hospital stay was 11.5 days (range: 7-54). At a mean follow-up of 24.9 months, 8 patients (36.4%) had disease recurrence (36.4%), global survival rate was 62.5%, and diseasefree survival rate was 50%. CONCLUSIONS: Assisted laparoscopic transhiatal esophagectomy for lower third esophageal cancer is a potentially safe and effective method when performed by surgeons with expertise in the field. Benefits from this approach need to be confirmed by further randomized studies.

Epidemic and Non-Epidemic Hot Spots of Malaria Transmission Occur in Indigenous Comarcas of Panama.

From 2002-2005, Panama experienced a malaria epidemic that has been associated with El Niño Southern Oscillation weather patterns, decreased funding for malaria control, and landscape modification. Case numbers quickly decreased afterward, and Panama is now in the pre-elimination stage of malaria eradication. To achieve this new goal, the characterization of epidemiological risk factors, foci of transmission, and important anopheline vectors is needed. Of the 24,681 reported cases in these analyses (2000-2014), ~62% occurred in epidemic years and ~44% in indigenous comarcas (5.9% of Panama's population). Sub-analyses comparing overall numbers of cases in epidemic and non-epidemic years identified females, comarcas and some 5-year age categories as those disproportionately affected by malaria during epidemic years. Annual parasites indices (APIs; number of cases per 1,000 persons) for Plasmodium vivax were higher in comarcas compared to provinces for all study years, though P. falciparum APIs were only higher in comarcas during epidemic years. Interestingly, two comarcas report increasing numbers of cases annually, despite national annual decreases. Inclusion of these comarcas within identified foci of malaria transmission confirmed their roles in continued transmission. Comparison of species distribution models for two important anophelines with Plasmodium case distribution suggest An. albimanus is the primary malaria vector in Panama, confirmed by identification of nine P. vivax-infected specimen pools. Future malaria eradication strategies in Panama should focus on indigenous comarcas and include both active surveillance for cases and comprehensive anopheline vector surveys.

[Knowledge, attitudes and practices regarding malaria in the indigenous Guna population of the Madungandí region, Panamá, 2012]. / Conocimientos, actitudes y prácticas sobre la malaria en la población indígena guna de la comarca de Madungandí, Panamá, 2012.

INTRODUCTION: Knowledge, attitudes and practices surveys allow to determine the degree of knowledge on the management of malaria in a given population, as well as the attitudes and practices that contribute or not to its transmission. OBJECTIVE: To identify the knowledge, attitudes and practices that favor or not the transmission of malaria in the indigenous Guna population of Madungandí. MATERIALS AND METHODS: A cross-sectional study was conducted by applying a survey to the heads of the families in a sample of 40% of households in three communities with high malaria incidence. Local Guna residents and translators were part of the research team that applied the questionnaires. The statistical analysis was performed in Epi-Info 6.04. RESULTS: The age range of those surveyed was between 20 and 70 years. All responders indicated that they belonged to and spoke the language of the Guna ethnic group, 64% were male and 30% were illiterate. Half (51%) of the responders declared they had suffered malaria at least once in the last eight years, and 89% accepted that malaria was a health problem. Sixty-three per cent responded that their traditional doctors, “inadule”, cured malaria and 7.0 % practiced the “pipe smoking” and “cocoa burn” rituals to prevent the disease. CONCLUSION: Considering the limited knowledge about malaria and its vector, as well as the willingness to collaborate shown by the Guna population, it is essential to initiate educational and participative programs to improve control and prevention activities in the communities aimed at achieving a reduction in malaria incidence in the Madungandí indigenous region.

Public health incident management: Logistical and operational aspects of the 2009 initial outbreak of H1N1 influenza in Mexico.

Hosting an international outbreak response team can pose a challenge to jurisdictions not familiar with incident management frameworks. Basic principles of team forming, organizing, and executing mission critical activities require simple and flexible communication that can be easily understood by the host country's public health leadership and international support agencies. Familiarity with incident command system principles before a public health emergency could save time and effort during the initial phases of the response and aid in operationalizing and sustaining complex field activities throughout the response. The 2009 initial outbreak of H1N1 in Mexico highlighted the importance of adequately organizing and managing limited resources and expertise using incident management principles. This case study describes logistical and operational aspects of the response and highlights challenges faced during this response that may be relevant to the organization of public health responses and incidents requiring international assistance and cooperation.

Public health incident management: logistical and operational aspects of the 2009 initial outbreak of H1N1 influenza in Mexico.

Hosting an international outbreak response team can pose a challenge to jurisdictions not familiar with incident management frameworks. Basic principles of team forming, organizing, and executing mission critical activities require simple and flexible communication that can be easily understood by the host country's public health leadership and international support agencies. Familiarity with incident command system principles before a public health emergency could save time and effort during the initial phases of the response and aid in operationalizing and sustaining complex field activities throughout the response. The 2009 initial outbreak of H1N1 in Mexico highlighted the importance of adequately organizing and managing limited resources and expertise using incident management principles. This case study describes logistical and operational aspects of the response and highlights challenges faced during this response that may be relevant to the organization of public health responses and incidents requiring international assistance and cooperation.

[Determining the status of susceptibility to organophosphate, carbamate and pyrethroids insecticides in populations of Aedes aegypti Linneaus, 1762 (Diptera: Culicidae) in Panamá]. / Determinación de la sensibilidad a insecticidas organofosforados, carbamato y piretroides en poblaciones de Aedes aegypti Linneaus, 1762 (Díptera: Culicidae) de Panamá

INTRODUCTION: We studied the susceptibility to organophosphate, carbamate and pyrethroid insecticides of Aedes aegypti from different regions of high transmission risk for dengue in Panama. OBJECTIVE: To evaluate the susceptibility to organophosphate, carbamate and pyrethroid insecticides in Ae. aegypti from eight sites belonging to seven municipalities in Panamá. MATERIALS AND METHODS: We collected Ae. aegypti larval populations in different types of breeding sites located in urban areas. Insects were reared in laboratory control conditions. With the F 1 generation of each strain we performed susceptibility bioassays using WHO standardized methodology for larvae and adults. RESULTS: The eight Ae. Aegypti strains were susceptible to the pyrethroid insecticides: deltamethrin, lambdacyhalothrin and cifluthrin, to the organophosphate fenitrothrion, and to the carbamates propoxur and bendiocarb. Only the CHITRE strain exhibited a moderate resistance to the insecticide deltamethrin in larvae (FR 50 =5x). However, adults were susceptible. CONCLUSIONS: It is necessary to perform periodic surveillance to evaluate the susceptibility of Ae. aegypti populations in the studied municipalities with the purpose of preserving their susceptible. The insecticides applied for Ae. aegypti control can still be used in the evaluated municipalities; however it will depend on the susceptibility of the mosquitoes in the specific area.

Novel genetic diversity within Anopheles punctimacula s.l.: phylogenetic discrepancy between the Barcode cytochrome c oxidase I (COI) gene and the rDNA second internal transcribed spacer (ITS2).

Anopheles punctimacula s.l. is a regional malaria vector in parts of Central America, but its role in transmission is controversial due to its unresolved taxonomic status. Two cryptic species, An. malefactor and An. calderoni, have been previously confused with this taxon, and evidence for further genetic differentiation has been proposed. In the present study we collected and morphologically identified adult female mosquitoes of An. punctimacula s.l. from 10 localities across Panama and one in Costa Rica. DNA sequences from three molecular regions, the three prime end of the mitochondrial cytochrome c oxidase I gene (3' COI), the Barcode region in the five prime end of the COI (5' COI), and the rDNA second internal transcribed spacer (ITS2) were used to test the hypothesis of new molecular lineages within An. punctimacula s.l. Phylogenetic analyses using the 3' COI depicted six highly supported molecular lineages (A-F), none of which was An. malefactor. In contrast, phylogenetic inference with the 5' COI demonstrated paraphyly. Tree topologies based on the combined COI regions and ITS2 sequence data supported the same six lineages as the 3' COI alone. As a whole this evidence suggests that An. punctimacula s.l. comprises two geographically isolated lineages, but it is not clear whether these are true species. The phylogenetic structure of the An. punctimacula cluster as well as that of other unknown lineages (C type I vs C type II; D vs E) appears to be driven by geographic partition, because members of these assemblages did not overlap spatially. We report An. malefactor for the first time in Costa Rica, but our data do not support the presence of An. calderoni in Panama.

Amblyomma tapirellum (Acari: Ixodidae) collected from tropical forest canopy.

Free-ranging ticks are widely known to be restricted to the ground level of vegetation. Here, we document the capture of the tick species Amblyomma tapirellum in light traps placed in the forest canopy of Barro Colorado Island, central Panama. A total of forty eight adults and three nymphs were removed from carbon dioxide-octenol baited CDC light traps suspended 20 meters above the ground during surveys for forest canopy mosquitoes. To our knowledge, this represents the first report of questing ticks from the canopy of tropical forests. Our finding suggests a novel ecological relationship between A. tapirellum and arboreal mammals, perhaps monkeys that come to the ground to drink or to feed on fallen fruits.

[Characterization of Plasmodium vivax malaria transmission at the border of Panamá and Costa Rica]. / Caracterización de la transmisión de la malaria por Plasmodium vivax en la región fronteriza de Panamá con Costa Rica en el municipio de Barú, Panamá

INTRODUCTION: Few studies have described the factors associated with Plasmodium vivax transmission dynamics in endemic regions from Panamá. OBJECTIVE: Malaria transmission dynamics produced by P. vivax were characterized at the border between Panamá and Costa Rica. MATERIALS AND METHODS: In the municipality of Barú, an observational, descriptive and cross-sectional study was undertaken to measure the annual parasite index (API), slide positivity index (SPR), and the annual blood examination rate (ABER). The most frequent symptoms and signs in malaria patients were recorded. The anopheline species were identified in the area and the preferred larval habitats, the density of larval populations in the larval habitats and the bites/human/night were characterized. RESULTS: Of a total of 10,401 thick smear blood samples, 83 were positive for P. vivax. Of these, 84% came from rural areas and 79% were from economically active individuals. The median and average ages were 36 and 30 years, respectively, and 58.5% of the malaria cases were male. API was 4.1/1,000 inhabitants; SPR was 0.8% and ABER was 51.9%. Of the diagnosed cases, 54% showed blood parasitemias ranging between 100-2,000 parasites/µl. The majority of the cases were observed in May and June. Two mosquito vector species were identified-- Anopheles albimanus and An. punctimacula. CONCLUSION: These observations indicate the advisibility of continued entomological studies, strengthening of epidemiological surveillance, consideration of additional risk factors and evaluation of work performance in the border region. This will require coordination with health authorities of both countries to control malaria in this region.

Reciprocal tripartite interactions between the Aedes aegypti midgut microbiota, innate immune system and dengue virus influences vector competence.

Dengue virus is one of the most important arboviral pathogens and the causative agent of dengue fever, dengue hemorrhagic fever, and dengue shock syndrome. It is transmitted between humans by the mosquitoes Aedes aegypti and Aedes albopictus, and at least 2.5 billion people are at daily risk of infection. During their lifecycle, mosquitoes are exposed to a variety of microbes, some of which are needed for their successful development into adulthood. However, recent studies have suggested that the adult mosquito's midgut microflora is critical in influencing the transmission of human pathogens. In this study we assessed the reciprocal interactions between the mosquito's midgut microbiota and dengue virus infection that are, to a large extent, mediated by the mosquito's innate immune system. We observed a marked decrease in susceptibility to dengue virus infection when mosquitoes harbored certain field-derived bacterial isolates in their midgut. Transcript abundance analysis of selected antimicrobial peptide genes suggested that the mosquito's microbiota elicits a basal immune activity that appears to act against dengue virus infection. Conversely, the elicitation of the mosquito immune response by dengue virus infection itself influences the microbial load of the mosquito midgut. In sum, we show that the mosquito's microbiota influences dengue virus infection of the mosquito, which in turn activates its antibacterial responses.